Route

A route is the base of a Marey chart. A Marey chart is essentially a fancy time-distance graph with a bunch of lines on it, where each line represents a trip. On the Marey chart, a line intersection means two vehicles on the trip meet. If the route only has one lane (e.g. the case for single-track railways), an intersection means a collision. If the route has two lanes, an intersection is only a collision when the lines’ slope are both positive or both negative. The tool has been used in railway coordination for hundreds of years.

Despite the fact that most traffic networks are 3d (since they are in our three-dimensional world), They can be almost always expressed in 2d form, with the height information discarded. Marey charts take a step further by compressing the 2d space into 1d space. In other words, coordinates are simplified to milestones on a route.

Traditional software suffers when trying to model complicated networks, for example, when there are multiple routes connecting stations, or massive station throats. Paiagram’s route model is designed to work around those limitations. It is designed around Marey chart’s model, but with significant extensions.

Milestone (Nominal Distance)

Station milestones might be different from the length of the actual tracks connecting stations, and the milestone field accommodates that.

Canvas Length

User setting. Doesn’t affect data model. Canvas length only affects each interval’s appearence on the graph.

Nodes

The nodes in the interval are the most important part of the route data model. The canvas would use this progress info and display trip lines at different sections of the diagram. Each node is assigned a progress.

The progress is calculated using the following formula:

where ${𝐷}_{𝑠}$ is the shortest distance from the node to any starting nodes, and ${𝐷}_{𝑡}$ is the distance from the node to any ending nodes.